In order to suppress global warming, a reduction in emission of carbon dioxide into the air has recently been demanded.
A recovery method utilizing a chemical adsorption method may be mentioned as one of techniques for separation, recovery, and storage (carbon capture and storage) (hereinafter often referred to as “CCS”) and has played an important role in reducing carbon dioxide in combustion exhaust gases in boilers, for example, in thermal electric power stations, from the past.
The following techniques may be mentioned as typical CCS techniques. These techniques will be briefly described.
A combustion exhaust gas from a boiler is if necessary subjected to denitration, dust collection, desulfurization or the like and is then led into an absorption tower where the combustion exhaust gas is brought into contact with an absorbing solution. This allows CO2 in the combustion exhaust gas to be absorbed in the absorbing solution to remove CO2 from the combustion exhaust gas. The absorbing solution in which CO2 has been absorbed is heated, for example, by a heat exchanger and is then led into a regeneration tower where CO2 is released from the absorbing solution and recovered. On the other hand, the absorbing solution from which CO2 has been released within the regeneration tower is circulated into the absorption tower and is reutilized for absorption of CO2 in the combustion exhaust gas. An absorbing solution composed of an amine and water is suitable as an absorbing solution for use in such CCS techniques. In practicing CCS utilizing the chemical adsorption method, when operation is carried out in a plant for a long period of time, the absorbing solution containing the amine is deteriorated by heating and oxidation. The deterioration leads to a reduction in effective ingredients and the production of amine derivatives, organic acids, nitrosoamines derived from the ingredients of the absorbing solution.
Attention is needed so that amines constituting the absorbing solution, deterioration products thereof and the like are not leaked into an external environment from the absorption tower, the regeneration tower, and other CCS apparatuses. To this end, a method that recovers the amine constituting the absorbing solution and the deterioration products thereof, and a method that analyzes the recovered materials have been desired. In particular, for nitrosoamines that have been pointed out to be harm, further advanced recovery techniques and techniques for quantitative determination with a higher sensitivity have been demanded.
In the CCS techniques, the operation in a plant for a long period of time causes a deterioration in the amine absorbing solution by heating or oxidation. The deterioration often leads to a reduction in effective ingredients and production of amine derivatives, organic acids, nitrosoamines and the like. The absorbing solution containing these deterioration products is periodically replaced and, at the present time, is regenerated with an ion-exchange resin or subjected to combustion disposal. However, consideration is needed for the cost of disposal of a huge amount of amine compounds disposed and environments in disposal.